1. Field of the Invention
The present invention relates to a high-speed communications system including a subscriber line transmission unit and a subscriber station, and also to a method of configuring communications facilities for high-speed services. More particularly, the present invention relates to a high-speed communications system which provides subscribers with high-speed voice/data communication services over standard telephone lines, and to a method of configuring transmission equipment for high-speed voice/data communication services.
2. Description of the Related Art
To meet the increasingly high demand for fast (e.g., from several hundred kbps to several Mbps) and inexpensive remote access, some new technologies have been introduced in recent years. The most promising of these technologies is the Digital Subscriber Line (DSL). The xDSL is a kind of modem technology which allows high-speed data transmission of several Mbps over ubiquitous, copper-wire telephone wiring infrastructure. Unlike the other existing standards such as V.34, the xDSL utilizes higher frequencies above 4 kHz, which is the upper limit of a frequency band for plain voice communications. Actually, some of the xDSL technologies use a high frequency range from several kHz to 1 MHz.
There are a few versions of xDSL technologies, targeting different data rates and transmission distances. Asymmetric DSL (ADSL) is the most popular specifications among the xDSL family technologies. To make ADSL services available, local carriers have to deploy ADSL modems and splitters in their central offices, and the users (or subscribers) should place similar equipment at their sites. They can enjoy Internet access with enhanced performance of their new communications environment that offers 8 Mbps (max) for downstream and 1 Mbps (max) for upstream data transmission, without changing their old telephone sets or replacing the telephone lines (or subscriber loops) that reach them. As such, the xDSL is a low-cost solution for high-speed network communication with the maximum utilization of existing telecommunications infrastructure.
In actual implementations of xDSL services, however, it is necessary for local carriers to upgrade existing telecommunications equipment at their central offices by installing some new components, such as ADSL modems and splitters. That is, more and more xDSL components should be installed, as the number of requesting users increases. Local carriers would face difficulties in their operations since the above upgrade requires more floor space to accommodate new components and needs more engineering work for cabling to interconnect them.
Taking the above into consideration, a first object of the present invention is to provide a high-speed communications system which permits high-speed communication services to be readily implemented with minimum modification to the existing communications facilities.
Also, a second object of the present invention is to provide a subscriber line transmission unit which permits high-speed communication services to be implemented with minimum modification to the existing communications facilities.
Further, a third object of the present invention is to provide a subscriber station which offers high-speed communication services.
Moreover, a fourth object of the present invention is to provide a method of enabling high-speed services with minimum modification to existing communications facilities.
To accomplish the above objects, according to the present invention, there is provided a high-speed communications system which provides high-speed communication services over subscriber lines. This system comprises the following elements:
(a) a subscriber line transmission unit located in a central office, comprising:
(a1) a multiplexer/demultiplexer unit which multiplexes outgoing signals to a network and demultiplexes incoming signals from the network, separately for voice signals and data signals,
(a2) a first voice processing unit, linked to a voice service subscriber who only uses voice communication services, which processes the voice signals for bidirectional communications over the subscriber line,
(a3) a second voice processing unit, linked to a voice/data service subscriber who uses both voice and data communication services, which processes the voice signals for bidirectional communication, and
(a4) a high-speed communications control unit comprising:
(a4-1) an office-side modem unit for processing the data signals to provide the voice/data service subscriber with bidirectional communication services, and
(a4-2) an office-side splitter unit for separating the voice signals and the data signals when providing the voice/data service subscriber with bidirectional communication services;
(b) a subscriber station disposed at a site of the voice/data service subscriber, comprising:
(b1) a subscriber-side splitter unit, coupled to the office-side splitter unit through the subscriber line, for separating the voice signals and the data signals, and
(b2) a subscriber-side modem unit for processing the data signals to provide the voice/data service subscriber with bidirectional communication services.
The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate a preferred embodiment of the present invention by way of example.